The research outlined in this proposal is designed to contribute to our very limited knowledge of the toxicology of halogenated fatty acids. Initial studies will concentrate on brominated fatty acids because of their use in food additives and flame retardants and their occurrence in marine oils. Brominated vegetable oils have been shown to be cardiotoxic and the active constituents of the oil will be established by conventional feeding studies with rats comparing the effects of the oil to those produced by the various constituents of the oil. Analytical procedures will be developed for brominated fatty acids which will allow identification of these components in commercial products and marine oils. Having established which components of brominated oils are toxic, subsequent studies will be concerned with their metabolism and distribution in the rat. Dose-response relations will be developed and the effect of the stage of development of the rat on the induction of the lesion evaluated. The reversibility of the induced changes will be observed. Of particular interest is the possible interaction of a brominated fatty acid and erucic acid, a naturally-occurring fatty acid which is also cardiotoxic.